Method of forming wax slabs



IN VEN TOR.

S. W. FERRIS Filed July 21, 1948 kN QN METHOD OF FORMING WAX SLABS May 15, 1951 9 H230 F X Affarn e s slabs.

Patented May 15, 1951 7 2,553,365 METHOD or FORMING WAX SLABS Seymour W. Ferris, Mount Holly, N. J., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Application July 21, 1948, Serial No. 39,995

2 Claims.

This invention relates to the forming of wax In its general aspect, the invention is concerned with the formation of wax sheets by a process enabling positive control of continuous manufacture. Specifically, the invention provides an improved method for manufacturing wax slabs or sheets directly from molten wax without any requirements for prehandling or conditioning the wax prior to introducing it to the forming process.

The present invention has particular utility in the production of petroleum waxes in shapes conforming to commercial requirements. It has long been the practice to cast wax in chilled molds whereby the finished product required long periods of time to solidify sufficiently for handling. Attempts have been made to continuously manufacture wax slabs by extruding a prechilled, finely divided Wax as a ribbon either on water or a moving surface such as conveyor belts. Both the methods of casting and extruding require expensive equipment and are open to other objections which are eliminated by the disclosed method.

It is, therefore, the principal object of this invention to disclose a process for the continuous production of wax slabs of commercial quality from wax in the molten state without intervening preparation.

Another object is to eliminate long chilling periods and place the Wax in a form easily handled for packaging and shipping in a minimum time.

According to the present invention these objects, and others which will become evident in the further description of the process, are attained by flowing molten wax on a flowing body of liquid coolant, nonmiscible with wax, and transferring the solidified wax thus formed through successive chilling loci as to attain the temperature of the wax sheet desired. 7

In the accompanying drawing there is shown, for purposes of illustration, apparatus adapted to the operation of the process of this invention.

In the drawing, in which like reference characters denote like parts:

Figure 1 depicts in diagrammatic form, an arrangement of apparatus adapted to form the wax sheet in accordance with this invention.

Figure 2 illustrates a section on line 2-2 of Figure 1.

Preliminary to detailing one form of equipment which may be used in practicing this invention, an outline of the principal steps involved will clarify the process. The molten wax,

' received directly from the stills or storage tanks,

is passed through a flow control and spreader to the flowing body of liquid coolant. The initial set of the wax sheet takes place as it flows on the liquid in a solidification zone. A succession of chilling zones, determined by the initial temperature and the bulk of the wax, reduces the temperature of the sheet or cake to the desired degree. Then follow the steps of cutting and packaging.

In the drawing, Figure 1 illustrates, diagrammatically, a receptacle H1 in which the molten wax is received directly from a conduit l l which in turn, is connected to a source of molten wax not shown. A heating coil l2 continues the wax in molten condition permitting it to flow through aperture [3 at the bottom of container l0 and thence directly onto a body of liquid coolant M which flows below container IE], in the initial solidifying zone.

The liquid coolant I4 is regulated to flow through a wide trough 15 in a, direction concurrent with the flowing deposit of wax l6 on its surface. The trough I5 is sufficiently wide so that at no time does the molten wax l6 touch the sides, and is sufliciently deep to prevent the deposited wax from scraping the bottom. Once the wax is received in the liquid coolant it floats and continues through the process. The flow of the liquid coolant in this initial solidification zone, is controlled by pump ll which forms part of the circulatory system. The temperature of the liquid coolant is maintained as required by heater I8 and cooler l9 both of which are maintained in the coolant circulation system. A weir 29 is installed in the flow of the liquid coolant immediately before the locus of deposit of the molten wax in the cooling trough, to remove all liquid surges and present a smoothly flowing body of liquid coolant to receive the molten wax. The same body of liquid coolant is recirculated through the zone after being returned to the pump I! from the overflow receiver 2!.

A, chilling section is illustrated for further reducing the temperature of the flowing wax form and is indicated by trough 23. A roller 22 is installed to transmit the motion of the progressing wax ribbon, and suspend it, in transfer from the initial solidification section to the chilling section. The water pump 24 and cooling unit 25 are similar to those already discussed with reference to the first section and assist the flow of the liquid coolant at the proper temperature. A heater is not required in the circulatory system of this zone, or successive chilling zones, as the initial temperature differential between the melting point of the Wax and the liquid coolant need not be maintained here. This temperature differential and the reason for it are discussed later in the specification. A Weir 26 is also used in the chilling section immediately preceding the point where the wax sneet enters the nowing liquid coolant and performs as described above in relation to the solidification section. An overflow receiver 2': receives the liquid coolant as in the circulation system of the solidification zone previously described. a v

It will be understood that a number of chilling sections or zones may be used, dependent upon the retained temperature in the moving wax slab, so as to present a crystallized product of required temperature prior to being received at the cutting and packing table or for any other manipulation where a comparatively solid wax body is required.

Assuming one chilling section only is required as illustrated, an additional roller 28 assists the flowing wax ribbon to enter cutting knives 29, illustrated diagrammatically, where it is cut to required size. An air blast 30 is indicated as one means to assist the removal of the liquid coolant from the finished wax form preliminary to cutting and further handling.

Figure 2 illustrates a section through the solidification zone showing the elevation of the aperture [3 through which the molten wax ribbon I6 emerges to enter the flowing body of the liquid coolant. The Width of the trough l illus trates that no contact is made with the sides or the lower portion of the wax sheet as it floats in the body of the liquid coolant l4.

In the operation of the process, it has been found by experiment that the flow of the molten wax from the reservoir II] should be maintained at the rate of flow of the liquid coolant and should enter thebody of the liquid coolant in a manner to smoothly continue to flow in the same direction as the coolant. It has been discovered that this procedure permits the manufacture of a smooth wax slab of commercial color and texture free of any ripples on the wax surface. Maintaining the flow of the wax and the surface of the liquid coolant at a rate of flow of approximately 8 ft. per minute has given very satisfac: tory results although reasonable variations above or below this rate, between 4 and 16 ft.per minute, may safely be used. This does not necessarily indicate that the subsurface of the liquid is flowing at that same rate. Consequently, to disturb the wax sheet in the heated condition as little as possible, it is necessary that the trough containing the liquid coolant in the solidification zone be sufficiently deep and sufiiciently Wide as to permit the free passage of the molten Wax along the liquid surface without contacting the trough body.

The liquid coolant used in the process should be a fiuid of a specific gravity greater thanthe wax. It should be nonmiscible with the wax and capable of maintaining a reasonably constant temperature. In most instances water has been found to be a satisfactory medium but might not be satisfactory under conditions for forming Wax slabs from all possible wax sources. It has been determined that the best results are obtained when the temperature of the liquid coolant in the solidification zone where the molten Wax initially contacts the flowing body of coolant is 20-60 F. below the temperature of the melting point of the wax. It is to maintain this temperature differential that both a heater and a cooler have been diagrammatically indicated in the coolant circulatory system in this zone.

Wax sheets produced by this method have been found to generally conform in cross-section to the size and shape of the slot in the wax reservoir which is used to deposit the molten wax on the surface of the liquid coolant. Therefore, considerable flexibility iS available with the process disclosed in the manufacture of a variety of slabs in different thicknesses to meet market demands.

The process of this invention may be practiced with many types of mechanical equipment in many combinations. It is not the intention of the inventor to be restricted to any one form. The device here illustrated is offered as one way to achieve the results of his discovery.

I claim:

1. The process for the manufacture of wax sheets consisting in continually delivering a ribbon of molten wax of predetermined width and thickness onto and in direct contact with the surface of a flowing stream of non-miscible liquid coolant of substantially greater width than that of the ribbon of molten wax and of a depth sufficiently great to prevent the wax ribbon, in its partial submergence, from sinking to the bottom of the liquid coolant stream, said molten wax ribbon moving in the same direction and at the same rate as the stream of liquid coolant, and maintaining 9 C temperature of the nonmiscible liquid suificiently below that of the molten wax to effect cooling and solidification into a smooth, unrippled sheet before passing out of contact with the flowing liquid coolant stream. I

2. The process set forth in claim 1 in which the temperature of the liquid coolant, at the zone where the molten wax initially contacts the flowing coolant stream, is between 20 F. and 60 F. below the temperature of the melting point of the Wax. v r V SEYMOUR W. FERRI'S.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 7 661,250 Lombardi Nov. 6, 1900 1,321,401 Sommer Nov. 11, 1919 1,920,118 Walsh July 25, 1933 2,219,700 Perrin Oct. 29, 1940 

1. THE PROCESS FOR THE MANUFACTURE OF WAX SHEETS CONSISTING IN CONTINUALLY DELIVERING A RIBBON OF MOLTEN WAX OF PREDETERMINED WIDTH AND THICKNESS ONTO AND IN DIRECT CONTACT WITH THE SURFACE OF A FLOWING STREAM OF NON-MISCIBLE LIQUID COOLANT OF SUBSTANTIALLY GREATER WIDTH THAN THAT OF THE RIBBON OF MOLTEN WAX AND OF A DEPTH SUFFICIENTLY GREAT TO PREVENT THE WAX RIBBON, IN ITS PARTIAL SUBMERGENCE, FROM SINKING TO THE BOTTOM OF THE LIQUID COOLANT STREAM, SAID MOLTEN WAX RIBBON MOVING IN THE SAME DIRECTION AND AT THE SAME RATE AS THE STREAM OF LIQUID COOLANT, AND MAINTAINING THE TEMPERATURE OF THE NONMISCIBLE LIQUID SUFFICIENTLY BELOW THAT OF THE MOLTEN WAX TO EFFECT COOLING AND SOLIDIFICATION INTO A SMOOTH, UNRIPPLED SHEET BEFORE PASSING OUT OF CONTACT WITH THE FLOWING LIQUID COOLANT STREAM. 